Beauveria bassiana (Hyphomycetes: Moniliales) Infection During Ecdysis Of Silkworm Bombyx Mori (Lepidoptera: Bombycidae)

Abstract :

Mulberry silkworm, Bombyx mori is the most commercially exploited insect which is domesticated worldwide for the production of silk cocoons. Domestication and constant rearing for the past several thousands of years made the silkworm highly susceptible to different pathogens. Different micro-organisms such as viruses, bacteria, fungi and microsporidia cause infectious diseases in silkworm. White muscardine caused by the fungal pathogen Beauveria bassiana is one of the most common and devastating diseases of silkworm. All the life stages of silkworm are susceptible to B. bassiana and its infection to silkworm during ecdysis (moulting) is studied and discussed in the present paper. The silkworms were inoculated with the pathogen at 1 × 105 conidia/ml dose at different durations (18, 12 and 6 hours) before and after moult. Inoculation was also done during the moult. Mortality was 100% when the inoculation was done 12 hours before and 6 hours after moulting. Mortality was significantly less when the larvae were inoculated during moulting or 6 hours before moult. The present findings indicate the inability of B. bassiana to invade the silkworm during its moulting period. Skin casting and related processes during ecdysis may be preventing the fungus to enter inside the haemocoel of silkworm to cause infection and mortality

Keyword :

Beauveria bassiana, silkworm, Bombyx mori, moulting

Author(s) : Chandrasekharan, K., Nataraju, B.
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Published Issue : 2011 Vol. 6 Number 1

2011 Vol. 6 Number 1